climate is not that harsh and do add in naltar as well in your itenary. PTDC motels are a better choice usually. July is the one of the best month for clear weather and successful flights for Skardu/Gilgit/Naltar.
if by road, it has no safety problem as there are thousands of tourists and local travel on it day and nights.
You can choose another route from Chilas via naran Kaghan Road instead of KKH which is very scenic and shorter as well, which will be open in June July onward uptil novermber.
KKH as major part of the road you have to go through Haraza division/kohistan region, formally called it NWFP. Well & good if you can fly from Islamabad to skardu, in case not than why not going through Babusar pass, this is shortest and more safe road one can enter in to GB. This year, I went many times through the said road and of course the scenarios are more charming compare to other road that usually people taking drive on it.
You should try Eagles Nest hotel at Hunza karimabad. Skardu is a wonderful place to be with a family,must not miss visiting Khaplu,Hushe valley,Satpara,Kachura & Shangrila hotel.
Also there are many transport companies run direct buses to Skardu and their names are NATCO, K2Travel, HImalaya Travel.
Again the direct driving hours from Islamabad to Skardu is about 27-30 hours.
Besides Gilgit Serena is charging 5500 for two per night per room, and PTDC is charging 4500 per night. ( approximately or more )